Science Reading Questions Reading: "The Periodic Table and Periodic Law"
1. The modern periodic table has come a long way since Lavoisier’s time when it was simply a list containing the 23 known elements of the time. Since then many scientists have tried to find the best organizational scheme. One such scientist was John Newlands who noticed that by arranging the elements in order of increasing atomic mass their properties were repeated every eighth element. Another scientist; Dimitri Mendeleev then followed Newland’s idea and arranged the elements in order of increasing atomic mass into columns with similar properties, thus creating the first periodic table.
The arrangement of the modern periodic table is greatly due to Henry Moseley, who discovered that atoms of each element contained a certain number of protons in their nucleus, which were equal to the element’s atomic number. Using this knowledge, he organized the elements in order of increasing atomic number; resulting in the modern periodic table we now know.
2. Sketch done on piece of paper.
3. Metals are normally solid at room temperature, good conductors of heat and electricity and are usually shiny when smooth and clean. Most metals are also malleable and ductile. Nonmetals are usually gases or brittle, hard-looking solids; apart from Bromine which is the only nonmetal that is liquid at room temperature. They are also poor conductors of heat and electricity. Metalloids are a cross between nonmetals and metals as they have physical and chemical properties from both groups.
4.
a.) Lithium (Li) is a Representative element.
b.) Platinum (Pt) is a Transition element.
c.) Promethium (Pm) is a Transition element.
d.) Carbon (C) is a Representative element.
5.
a.) Astatine (At) and Bromine (Br) have similar chemical properties to Iodine (I) as they are both found in the same group.
b.) Strontium (Sr) and Calcium (Ca) have similar chemical properties to Barium (Ba)
c.) Ruthenium (Ru) and Osmium (Os) have similar chemical properties to Iron (Fe)
6. The element with similar chemical behaviour to Silicon (Si) and Lead (Pb) with a mass greater than Sulfur (S) and less than Cadmium (Cd) is Germanium (Ge) as it is the only other element in that group which is within the specified mass range.
Science Reading Questions Reading: "The Structure of the Atom" 1. Democritus’s ideas were rejected by other philosophers of his time because he could not answer or explain what held atoms together as he did not know. Also his ideas did not agree with the ideas of other philosophers of the time.
2. An atom is the smallest building block of everything around us
3. Dalton believed that atoms were indivisible; however, modern atomic theory shows that atoms can be divided into several subatomic particles. He also believed that all atoms of any element have identical properties, but modern theory shows that atoms of an element can have different masses.
4. Democritus reached his theory through thinking about the world around him and matter and wondering what it was all made up of, eventually he came to the conclusion that all matter was made u of tiny particles called “atomos.” Dalton reached his theory through looking at Democritus’s theory and conducting research. He performed various experiments and studied many chemical reactions, carefully making observations and taking measurements while he did so.
Democritus’s ideas hampered the acceptance of his theory because his ideas were too far ahead for his time and he was not able to experiment in the way that Dalton could as science was not anywhere near as advanced as it was in Dalton’s time.
5. Democritus and Dalton had rather similar theories. They both believed that everything was made u of atoms and that changes in matter were the result of a change in the grouping of atoms. They also believed that atoms could not be destroyed or divided. However their theories are also different in a few ways. Democritus believed that there were different kinds of atoms, while Dalton believed that all atoms of a given element are identical and different from those of any other elements. Dalton also believed that all matter was made up of extremely small particles called atoms, whereas Democritus believed that all matter was made of empty space through which atoms moved.
6. The experiments which led to the conclusion of electrons being negatively charged involved the use of cathode ray tubes and magnets. When the experiments were carried out scientists noticed that the cathode ray was deflected, or pulled toward the positive side of the magnet which lead to the conclusion that the particles had a negative charge.
7. The typical atom is composed of three subatomic particles. There is a nucleus (the centre) which contains protons (positively charged) and neutrons (neutral charge). Around this, there are orbitals where the electrons (negative charge) are located. 8.
Subatomic Particle
Charge
Mass (amu)
Proton
0
1 (1.007 276)
Neutron
+
1 (1.008 665)
Electron
-
1/1840 (0.000 549)
9. Thomson’s plum pudding model suggested that electrons were distributed throughout a uniform positive charge, whereas Rutherford’s nuclear atomic model suggested that there was no uniform positive charge. Instead it suggested that electrons moved rapidly through an empty space surrounding the nucleus but were held within the atom by the positive charge of the nucleus and the attraction it created between the electrons and protons.
10. Timeline drawn on piece of paper. 11. a. Boron = Protons -5, Electrons-5, Neutrons-6 b. Platinum = Protons -78, Electrons-78, Neutrons-117 c. Radon= Protons -86, Electrons-86, Neutrons-136 d. Magnesium= Protons -12, Electrons-12, Neutrons-12
12. Dysprosium
13. Silicon 14. b. Calcium= Protons -20, Electrons-20, Neutrons-26 c. Oxygen= Protons -8, Electrons-8, Neutrons-9 d. Iron= Protons -26, Electrons-26, Neutrons-31 e. Zinc= Protons -30, Electrons-30, Neutrons-34 f. Mercury = Protons -80, Electrons-80, Neutrons-124 15. Boron-10 mass contribution = (10.013 amu)(0.198)= 1.982574 Boron-11 mass contribution = (11.009 amu)(0.802)= 8.829218 Atomic mass of Boron= 1.982574 + 8.829218 = 10.811792 amu 16. Seeing as the mass of Helium is 4.003 then it is more likely that Helium-4 is more abundant, if not then the average mass would have been brought down by a large number of Helium-3s and the average mass would have been 3 and not 4. Therefore, Helium-4 is more abundant. 17. Magnesium-23 mass contribution = (23.985 amu)(0.7899) = 18.9457515 Magnesium-24 mass contribution = (24.986 amu)(0.1000) = 2.4986 Magnesium-25 mass contribution = (25.982 amu)(0.1101) = 2.8606182 Atomic mass Magnesium = 18.9457515 + 2.4986 + 2.8606182 = 24.3049697 18. The number of protons identifies an atom as that of a particular element. The atomic number shows the number of protons present in the atom of a particular element. 19. An isotope is an atom that contains the same number of protons but has a different number of protons than the most abundant atom of that element. An example of this is potassium which has three isotopes; in one type of potassium there are 20 neutrons which is the most commonly found one (most abundant). Then there are other types of potassium with 21 neutrons and 22 neutrons. 20. Isotopes affect the mass of an element as the mass is an average of the isotopes and it is not usually a whole number because the mass of protons and neutrons are just a little bit more than 1 amu the values are slightly different which leads to decimals being used to calculate the mass more accurately. 21. Nitrogen-14 is more abundant in nature because the average mass is 14.007 and if Nitrogen-15 were more abundant the average mass would have to be higher than 14.007 and closer to or above 15 amu. 22. To calculate the average atomic mass you first need to find the mass contribution of each isotope. This is done by multiplying the atomic mass units by the abundance %. After each of the atomic mass contributions have been found for each isotope they are added together and the sum is the average atomic mass. Ex. For Boron: Boron-10 Mass= 10.013 amu Abundance= 19.8% = 0.198 Boron-11 Mass= 11.009 amu Abundance= 80.2% = 0.802 Boron-10 mass contribution = (10.013 amu)(0.198)= 1.982574 Boron-11 mass contribution = (11.009 amu)(0.802)= 8.829218 Atomic mass of Boron= 1.982574 + 8.829218 = 10.811792 amu
Homework: Questions from reading:
1.Ozone is important because it absorbs most of the ultraviolet radiation before it reaches the Earth’s surface. This makes sit possible for living things to exist on Earth.
2. Ozone is formed in the upper regions of the stratosphere where oxygen gas is exposed to ultraviolet radiation.
3. CFCs (chlorofluorocarbons) are laboratory made chemicals consisting of chlorine, fluorine and carbon and they are used as coolants in refrigerators and air-conditioning units, propellants in spray cans and in plastic foams.
4.Ozone is formed when oxygen gas is exposed to ultraviolet radiation and as the equator receives the strongest of the sun’s rays it leads to ozone being formed in this region.
5.In general the graph shows ozone levels in the atmosphere declining over time.
6. Matter is anything that takes up space and has mass.
7. Both mass and weight are measurements of the amount of matter, however they are not the same as weight is more a measurement of Earth’s gravitational pull on that matter whereas mass is just the measurement of the amount of matter.
8. Chemistry involves the study of changes at a submicroscopic level because it helps to understand what causes changes seen at a macroscopic level. For example, at macroscopic level, you will notice that a leaf is green but if you only look at it at a macroscopic level you may never understand what makes that leaf green and why it is so. This is where chemistry comes in, chemistry allows us to dig deeper and to learn about what goes on beneath the surface of this leaf, it allows us to discover what reactions are occurring and what influences the colour of the leaf.
9.When synthesizing new chemicals with potential uses scientists must be very cautious as it could have many other effects and reactions to everything around us. This was seen in the case of CFCs, at first they seemed very useful and did not react to other chemicals but over time they caused ozone levels in the atmosphere to decrease. So, for any new chemical that is synthesized it is very difficult to predict what will happen and what effect it may have, therefore scientists need to be very cautious.
10. If weight is 120 pounds and mass is 54 kilograms then on the moon my mass would be the same (54 kilograms) and my weight would be 1/6 of that on Earth. This is because mass will not change whereas weight, which is basically a measurement of gravity’s pull will change. Therefore, as the moon’s gravitational force is 1/6 of Earths, my weight would be 20 pounds and my mass would be 54 kilograms
11. The scientific method is an organized process by which scientists do research and are able to verify the work of others. The steps vary from scientist to scientist but in general they are, observation, hypothesis, experiment and conclusion.
12.The independent variable would be the temperature as that is what you are putting in to the experiment. The dependent variable would be the size of the balloon and the constant would be the amount of air in the balloon. A control would have to be constructed and could be done by filling the balloon with air at room temperature and measuring it’s volume. Then it could be heated or cooled and the volume compared to that of the room temperature balloon.
13. Molina and Rowland’s hypothesis is strong in that there is evidence showing ozone levels decreasing while CFCs rise however it does have it’s weakness as well. As they are referring to ozone and CFC levels in the atmosphere it is difficult to say that there is a direct correlation between the two. This is because there are many other elements and chemicals present in the atmosphere which could have led to ozone levels decreasing. Or it could even be a natural process for ozone levels to vary just as temperatures on Earth have, moving from ice ages to heat waves and so forth. So, while there is evidence to suggest that their hypothesis is correct there are also other factors that weaken their hypothesis.
14.It should be a law because the gases will never change; therefore a certain temperature will always have the same effect on the volume of the gases at constant pressure. If gases were to change their properties or how they react to certain variables such as temperature then it would not be a law, but seeing as gases will always be what they are (oxygen will always be oxygen, helium will always be helium… etc.) and will always react in the same way that they do now then Charles’s description would be called Charles’s law.
15. Molina and Rowland’s data in the lab must be supported by measurements take in the stratosphere because the data collected in the lab will have been more controlled than that in the stratosphere. Therefore, the data in the lab could have had a completely different outcome to what the stratosphere data suggests; it could have been that under controlled circumstances CFCs do not impact ozone levels but in the stratosphere the more CFCs there are the less ozone there is. So data must be collected from both sources in order to see if there is a correlation between the two, which could be crucial in either supporting or rejecting their hypothesis. Also to prove a hypothesis they would have needed to collect as much data as they could to ensure an accurate conclusion.
16.It would be considered a hypothesis because if no data is provided then there is no evidence that it is true or even that it has been tested. For it to be a conclusion it would need data to support it so as there is no data it must be a hypothesis.
Questions for Chemistry:
1. How have we advanced in the study of medicine?
2. How are diseases cured?
3. How are we able to start fires from something as small as a match?
4. How are we able to think?
5. Why are certain crops able to withstand climates which they are not usually associated with?
6. Can we stop/cure mental illnesses?
7. Will we ever completely cure allergies?
8. Are “designer babies” actually a possibility?
9. Will airplanes ever be eco-friendly?
10. How are airplanes able to stay airborne?
pH and Temperature Collected Around The School
Letter
pH
Temp
A(under walkway)
6.51
25.9
B(by picnic table and tree)
7.62
25.6
C(under swing)
7.92
26.5
D (under swing)
8.03
26.6
E (in gutter)
7.18
26.1
F (under stairs)
8.18
25.5
G (green house)
8.04
26.1
H (rain gage)
6.48
27.9
I(fresh rainwater)
8.42
20.6
Untitled.png
The first thing that stands out about the graph and data is that there is no correlation between the pH and Temperature of the water. There are however pH levels which vary from 6.48 – 8.42 which is a bit odd as it was all rain water from the same day. This could suggest that there were things in the water which might have affected the pH, such as the mud, moss, leaves...etc. The temperature in general remained close to the same, varying but not much more than one degree C, until; the rain gage and fresh rainwater were tested. The rain gage had a temperature of 27.9 degrees C whereas the fresh rain water was 20.6 degrees C; as all of the other temperatures seemed to stay in the 25-26 degree range this was quite a significant drop in temperature. A possible explanation for this could be that all the other temperatures had been taken from water which had collected either on the ground outside or in a plastic rain gage, also outside. Which would have been exposed to the sun and heat before being tested so they would have had time to become warmer; whereas the fresh rainwater had been collected while it rained and was then kept indoors in a glass beaker. Another explanation could be that the ground may have been quite warm before the rain, so, as the rainwater collected, the heat of the surface or ground warmed the temperature before collection.
Blood Pressure Experiment (edited) Research Question:
How does blood pressure change in isometric training as compared to isotonic training? Hypothesis:
If blood pressure rises more when a person is performing exercises involving movement then the blood pressure will be higher in isotonic training as compared to Isometric training. Materials:
-blood pressure sensor
-pen & paper for any observations
-data logger
-computer
-gym mat
-wall
-2 or more volunteers Independent Variable: Type of exercise Dependent Variable: Blood pressure Control Group: Blood pressure while resting Experimental group: Blood pressure while/after resting Controlled Variables: Age of volunteer, amount of time for each exercise, exercise done, resting time between exercises Procedure: 1. Explain to the volunteers that they will be performing 4 different exercises each for a certain amount of time while their blood pressure is being collected. 2. Connect the data loger and blood pressure sensor to the computer and power supply and make sure everything is working. 3. Have the first volunteer sit while wearing the sensor for 30 seconds then press “collect.” Let the sensor run for 30 seconds and record the average resting blood pressure into the table. 4. Now have the same volunteer stand still and record the average standing blood pressure. 5. The same volunteer will now start the first exercise (sit-ups) for 30 seconds while the average blood pressure is recorded 6. Let the volunteer rest for 30 seconds then repeat the exercise for 45 seconds and record the average blood pressure 7. Repeat steps 5 & 6 for each of the chosen times, letting the volunteer rest for the same amount of time that they have exercised each time (ex. Exercise for 1 minute then rest for 1 minute then move on) 8. Let the same volunteer rest until the blood pressure goes back to the original sitting pressure 9. Repeat steps 3-8 with the same volunteer for push-ups 10. Repeat steps 3-8 with the same volunteer for the wall sit 11. Repeat steps 3-8 with the same volunteer for the plank 12. When the first volunteer has completed the first trial for all the exercises move on to the next volunteer and repeat steps 3-11 13. Once all the volunteers have repeated the first set of trials go back to step 3 and repeat everything for trial 2 14. Go back to step 3 and repeat everything for trial 3 15. Finally, graph the collected data and try to draw an accurate conclusion
For the wall sit the volunteer must have their back upright against the wall and their knees bent at a 90 degree angle and must hold this position for the entire course of the given time. For the plank the volunteer must get into the push-up position with their back straight and hold it for the entire length of time given.
Exercise, Isotonic
Blood Pressure Resting
Pressure After 30 sec. Exercise
Pressure After 45 sec. Exercise
Pressure After 1 min. Exercise
Pressure After 1min. 15 Exercise
Blood Pressure at End
Trial
Sit
Stand
1.
2.
3.
1.
2.
3.
1.
2.
3.
1.
2.
3.
Sit-ups
Push-ups
Exercise, Isometric
Wall sit
Plank
Blood Pressure Experiment
Research Question:
How does blood pressure change in isometric training as compared to isotonic training? VERY GOOD! Hypothesis: If blood pressure rises more with isotonic training/exercises then it will be higher than with Isometric training/exercises. This is unclear Jade, what is the prediction? Materials:
-blood pressure sensor
-pen & paper for any observations
-data log ger
-computer
-gym mat
-wall
-2 or more volunteers Independent Variable: Type of exercise Dependent Variable: Blood pressure Control Group: Blood pressure while resting Experimental group: Blood pressure while/after resting Where are your variables to be controlled Procedure: 1. Connect the data log and blood pressure sensor to the computer and power supply and make sure everything is working. 2. Have the first volunteer wear the sensor and press “collect.” Let the sensor run for 30 seconds and record the average resting blood pressure into the table. what is the volunteer doing to be resting? 3. Place the gym mat close enough to the data log so that the cables reach and the volunteer is able to move without interference. Explain to the volunteer that they will now have a certain amount of time in which they must try their best to complete the given exercise (you should also explain which exercise they are starting with (you will have to move everything near to a wall for the wall sit)). THIS SHOULD OCCUR PRIOR TO START,MIGHT THIS ALSO AFFECT BLOOD PRESSURE? 4. When the volunteer is ready press “collect” and let them begin. Let the data log run for the time set (30 sec., 45 sec., 1 min. or 1min.15) then stop the data log and record the average blood pressure. START WHAT? YOU NEED TO TELL WHICH EXERCISE. 5. After each exercise let the volunteer rest for the same amount of time that they have been working (ex. If the exercise lasted 45 seconds they will get 45 seconds of rest before the next one). 6. Repeat this process for each length of time, with 3 trials for each exercise and time. 7. Record the blood pressure at the very end aswell. SENSOR WILL RECORD THROUGHOUT . 8. Finally, look over the data collected and graph the results, then try to form a conclusion based on the collected data. You might have to repeat or change the experiment if necessary. NOT NEEDED.
For the wall sit the volunteer must have their back upright against the wall and their knees bent at a 90 degree angle and must hold this position for the entire course of the given time. For the plank the volunteer must get into the push-up position with their back straight and hold it for the entire length of time given. WHEN DOES THIS HAPPEN? YOU NEED TO BE SPECIFIC.
Exercise, Isotonic
Blood Pressure Resting
Pressure After 30 sec. Exercise
Pressure After 45 sec. Exercise
Pressure After 1 min. Exercise
Pressure After 1min. 15 Exercise
Blood Pressure at End
Trial
1.
2.
3.
1.
2.
3.
1.
2.
3.
1.
2.
3.
Sit-ups
Push-ups
Exercise, Isometric
Wall sit
Plank
THESE WILL BE DURING THE TEST AS WELL. OVERALL A GOOD JOB, YOU NEED TO WORK ON YOUR WORDING FOR YOUR METHOD/PROCEDURE . WELL WORDED QUESTION.
(homework) The Scientific Method
The scientific method is a process by which a problem is solved or a theory is tested. It can also be said that it is the base of everything that is done in science and many of our day-to-day processes whether we realize it or not, it is an essential part of science and life in general. If you really think about it, one way or another everything man-made around us has been made through some form of the scientific method. - good explanation dont have much to critisize
The scientific method involves several steps which are: making an observation/identifying a problem, forming a hypothesis (usually an “if…” and “then…” statement). Then carrying out experiments and making observations in order to test the hypothesis, collecting and analyzing data. (maybe more steps like research and what the hypthesis is) Finally, a conclusion is drawn and the initial hypothesis is either supported or rejected. If supported then the results are communicated or told to others. However, if the hypothesis is rejected then a new hypothesis can be formed and tested or the experimental stage can be re-done to make sure that there were no errors. Even though this process is known to all scientists and many others it does not mean that they will all list the same steps. For example, different sources on the internet will have a different number of steps or call them different names or even have them ordered differently. They might have research before the hypothesis or might group together different steps and not every source includes the communication of results at the end. Now this doesn’t mean that the scientific method has changed, it is still the same universal method, however, as everyone is different they will see it differently and many might find some steps unnecessary to list.
The scientific method, as you can imagine, is an essential part of a scientist’s daily work. Without it they would have nothing to test or discover. Scientists use the method in a variety of ways. For example, if a scientist suddenly notices that the plants on the right side of the room look healthier than those on the left and that it is lighter on the right side, then the scientific method has already been put into play. From here the scientist could say that if the plants on the right are receiving more sunlight then they will look healthier than those on the left. Then relevant research would be done and experiments carried out and so forth. This happens every day for scientists, who test and experiment with everything from the effect of coke on plant growth to cures for diseases like dengue or cancer, and discover things that make our lives better and easier which would not be possible without the scientific method.
Now it is not only scientists that use the scientific method, we use it as well, most of the time without realizing it. In math we use it to solve problems; in art we use it to create paintings and drawings. We even use it while driving to school. We think, “If I take this road then there will be less traffic” and we proceed to test this theory and then based on what time we get there we judge whether it was a good choice or not. In technology the design cycle is used which, if you think about it, is just like the scientific method. You start by investigating a problem then planning, creating a solution and finally evaluating your work. So, the scientific method is all around us whether we know it or not. ( good, which can be associated with anyone) - your everyday life situation, but you could expand on the situation theres not much to expand on, this is well done
Sources: http://scifiles.larc.nasa.gov/text/kids/Research_Rack/tools/scientific_method.html http://teacher.pas.rochester.edu/phy_labs/AppendixE/AppendixE.html http://sciencebuddies.com/science-fair-projects/project_scientific_method.shtml http://school.discoveryeducation.com/sciencefaircentral/Getting-Started/Investigation.html
pH Lab Materials - Data log some of this info was cut off the page but seems to be pretty good - Computer - pH sensor - Various liquids and household cleaners - Three 100ml beakers - A 400ml for the cooler water - Pen and paper to make observations Method
Before starting the experiment make sure that a table has been made including each liquid that will be tested with two additional columns one for the predicted pH and one for the actual pH. Also make sure to write your pH predictions before testing any of the liquids. 1. Connect the data log and pH sensor to a laptop/computer 2. Fill the 400ml beaker with roughly 200ml of cooler water (filtered water taken from the water cooler) then place the sensor in it. Click on “collect” and let the data log run for 30 seconds. 3. Stop the data log and find the average pH and either write it down or type it into a table. 4. Fill the three 100ml beakers each with 40ml a different solution and place the pH sensor in one of them, click “collect” and let it run for 30 seconds then record the average 5. Repeat this with each of the 3 beakers, making sure to rinse the pH sensor in the cooler water between each reading 6. After testing those liquids, empty, rinse and dry the beakers and choose another 3 different liquids and replace the cooler water, then repeat the process until all the liquids have been tested. 7. After all the results have been tested look through the table and compare the predicted pH to the actual pH, then make a graph and write your conclusion. *It is advised to test waters first (salt water, tap water, cooler water) and liquids such as lime juice, Disiclin and Cola last as they may affect other readings. - great method, lots of explanattion Data Table
Solution
Predicted pH
Actual pH
Average Predicted pH (1 d.p)
Average Actual pH (1 d.p)
Cola
2.3
2
3
2.3
2.576
2.6
2.4
2.5
Disiclin
14
9
8
4.9
5.373
5.64
10.3
5.3
Lime Juice
3
3
2
2.2
2.385
2.41
2.7
2.3
Tap Water
7.5
6
4
6.9
7.232
7.18
5.8
7.1
Cooler Water
7
7
7
6.49
6.567
8.62
7
7.2
Vinegar
3.5
3
2
2.2
2.463
2.4
2.8
2.4
Salt Water
6.5
6
8.5
6.52
6.842
6.9
7
6.8
50% Alcohol
5.5
13
2
10
7.89
8.233
4.65
7.6
6.9
Pure Alcohol
4
14
1
13
6.35
7
8.65
8
7.3
Results (graphed)
Conclusion/Evaluation
I think overall the predicted pH’s where quite close to the actual pH apart from the predictions for the two alcohols and the disiclin. Most of the groups thought that disiclin would be more of a base when in fact it turned out to be an acid; and the alcohols were thought o be either bases or acids but turned out to be quite close to 7 (the neutral). Another observation which is quite interesting to note is the difference in pH readings for the 50% alcohol. In all the other data the differences between the pH’s is usually off by one or two but in this case the pH readings were 7.89, 8.233 and 4.65 which is a bit strange because it was the same substance being tested but it gave two similar readings and one that was completely different. I think in the future if this lab were to be repeated a hypothesis should be created and the pH of the substances could be tested under various conditions to see if something like temperature could affect it or if the amount of time the sensor is in the beaker changes the pH.
Great job jade i have nothing to critisize haha really but maybe a bit of clarification on the odd sentance but other then that its good.
Science Reading Questions Reading: "The Periodic Table and Periodic Law"
1. The modern periodic table has come a long way since Lavoisier’s time when it was simply a list containing the 23 known elements of the time. Since then many scientists have tried to find the best organizational scheme. One such scientist was John Newlands who noticed that by arranging the elements in order of increasing atomic mass their properties were repeated every eighth element. Another scientist; Dimitri Mendeleev then followed Newland’s idea and arranged the elements in order of increasing atomic mass into columns with similar properties, thus creating the first periodic table.
The arrangement of the modern periodic table is greatly due to Henry Moseley, who discovered that atoms of each element contained a certain number of protons in their nucleus, which were equal to the element’s atomic number. Using this knowledge, he organized the elements in order of increasing atomic number; resulting in the modern periodic table we now know.
2. Sketch done on piece of paper.
3. Metals are normally solid at room temperature, good conductors of heat and electricity and are usually shiny when smooth and clean. Most metals are also malleable and ductile. Nonmetals are usually gases or brittle, hard-looking solids; apart from Bromine which is the only nonmetal that is liquid at room temperature. They are also poor conductors of heat and electricity. Metalloids are a cross between nonmetals and metals as they have physical and chemical properties from both groups.
4.
a.) Lithium (Li) is a Representative element.
b.) Platinum (Pt) is a Transition element.
c.) Promethium (Pm) is a Transition element.
d.) Carbon (C) is a Representative element.
5.
a.) Astatine (At) and Bromine (Br) have similar chemical properties to Iodine (I) as they are both found in the same group.
b.) Strontium (Sr) and Calcium (Ca) have similar chemical properties to Barium (Ba)
c.) Ruthenium (Ru) and Osmium (Os) have similar chemical properties to Iron (Fe)
6. The element with similar chemical behaviour to Silicon (Si) and Lead (Pb) with a mass greater than Sulfur (S) and less than Cadmium (Cd) is Germanium (Ge) as it is the only other element in that group which is within the specified mass range.
Science Reading Questions Reading: "The Structure of the Atom"
1. Democritus’s ideas were rejected by other philosophers of his time because he could not answer or explain what held atoms together as he did not know. Also his ideas did not agree with the ideas of other philosophers of the time.
2. An atom is the smallest building block of everything around us
3. Dalton believed that atoms were indivisible; however, modern atomic theory shows that atoms can be divided into several subatomic particles. He also believed that all atoms of any element have identical properties, but modern theory shows that atoms of an element can have different masses.
4. Democritus reached his theory through thinking about the world around him and matter and wondering what it was all made up of, eventually he came to the conclusion that all matter was made u of tiny particles called “atomos.” Dalton reached his theory through looking at Democritus’s theory and conducting research. He performed various experiments and studied many chemical reactions, carefully making observations and taking measurements while he did so.
Democritus’s ideas hampered the acceptance of his theory because his ideas were too far ahead for his time and he was not able to experiment in the way that Dalton could as science was not anywhere near as advanced as it was in Dalton’s time.
5. Democritus and Dalton had rather similar theories. They both believed that everything was made u of atoms and that changes in matter were the result of a change in the grouping of atoms. They also believed that atoms could not be destroyed or divided. However their theories are also different in a few ways. Democritus believed that there were different kinds of atoms, while Dalton believed that all atoms of a given element are identical and different from those of any other elements. Dalton also believed that all matter was made up of extremely small particles called atoms, whereas Democritus believed that all matter was made of empty space through which atoms moved.
6. The experiments which led to the conclusion of electrons being negatively charged involved the use of cathode ray tubes and magnets. When the experiments were carried out scientists noticed that the cathode ray was deflected, or pulled toward the positive side of the magnet which lead to the conclusion that the particles had a negative charge.
7. The typical atom is composed of three subatomic particles. There is a nucleus (the centre) which contains protons (positively charged) and neutrons (neutral charge). Around this, there are orbitals where the electrons (negative charge) are located.
8.
10. Timeline drawn on piece of paper.
11.
a. Boron = Protons -5, Electrons-5, Neutrons-6
b. Platinum = Protons -78, Electrons-78, Neutrons-117
c. Radon= Protons -86, Electrons-86, Neutrons-136
d. Magnesium= Protons -12, Electrons-12, Neutrons-12
12. Dysprosium
13. Silicon
14.
b. Calcium= Protons -20, Electrons-20, Neutrons-26
c. Oxygen= Protons -8, Electrons-8, Neutrons-9
d. Iron= Protons -26, Electrons-26, Neutrons-31
e. Zinc= Protons -30, Electrons-30, Neutrons-34
f. Mercury = Protons -80, Electrons-80, Neutrons-124
15. Boron-10 mass contribution = (10.013 amu)(0.198)= 1.982574
Boron-11 mass contribution = (11.009 amu)(0.802)= 8.829218
Atomic mass of Boron= 1.982574 + 8.829218 = 10.811792 amu
16. Seeing as the mass of Helium is 4.003 then it is more likely that Helium-4 is more abundant, if not then the average mass would have been brought down by a large number of Helium-3s and the average mass would have been 3 and not 4. Therefore, Helium-4 is more abundant.
17. Magnesium-23 mass contribution = (23.985 amu)(0.7899) = 18.9457515
Magnesium-24 mass contribution = (24.986 amu)(0.1000) = 2.4986
Magnesium-25 mass contribution = (25.982 amu)(0.1101) = 2.8606182
Atomic mass Magnesium = 18.9457515 + 2.4986 + 2.8606182 = 24.3049697
18. The number of protons identifies an atom as that of a particular element. The atomic number shows the number of protons present in the atom of a particular element.
19. An isotope is an atom that contains the same number of protons but has a different number of protons than the most abundant atom of that element. An example of this is potassium which has three isotopes; in one type of potassium there are 20 neutrons which is the most commonly found one (most abundant). Then there are other types of potassium with 21 neutrons and 22 neutrons.
20. Isotopes affect the mass of an element as the mass is an average of the isotopes and it is not usually a whole number because the mass of protons and neutrons are just a little bit more than 1 amu the values are slightly different which leads to decimals being used to calculate the mass more accurately.
21. Nitrogen-14 is more abundant in nature because the average mass is 14.007 and if Nitrogen-15 were more abundant the average mass would have to be higher than 14.007 and closer to or above 15 amu.
22. To calculate the average atomic mass you first need to find the mass contribution of each isotope. This is done by multiplying the atomic mass units by the abundance %. After each of the atomic mass contributions have been found for each isotope they are added together and the sum is the average atomic mass.
Ex. For Boron:
Boron-10
Mass= 10.013 amu
Abundance= 19.8% = 0.198
Boron-11
Mass= 11.009 amu
Abundance= 80.2% = 0.802
Boron-10 mass contribution = (10.013 amu)(0.198)= 1.982574
Boron-11 mass contribution = (11.009 amu)(0.802)= 8.829218
Atomic mass of Boron= 1.982574 + 8.829218 = 10.811792 amu
Homework: Questions from reading:
1.Ozone is important because it absorbs most of the ultraviolet radiation before it reaches the Earth’s surface. This makes sit possible for living things to exist on Earth.
2. Ozone is formed in the upper regions of the stratosphere where oxygen gas is exposed to ultraviolet radiation.
3. CFCs (chlorofluorocarbons) are laboratory made chemicals consisting of chlorine, fluorine and carbon and they are used as coolants in refrigerators and air-conditioning units, propellants in spray cans and in plastic foams.
4.Ozone is formed when oxygen gas is exposed to ultraviolet radiation and as the equator receives the strongest of the sun’s rays it leads to ozone being formed in this region.
5.In general the graph shows ozone levels in the atmosphere declining over time.
6. Matter is anything that takes up space and has mass.
7. Both mass and weight are measurements of the amount of matter, however they are not the same as weight is more a measurement of Earth’s gravitational pull on that matter whereas mass is just the measurement of the amount of matter.
8. Chemistry involves the study of changes at a submicroscopic level because it helps to understand what causes changes seen at a macroscopic level. For example, at macroscopic level, you will notice that a leaf is green but if you only look at it at a macroscopic level you may never understand what makes that leaf green and why it is so. This is where chemistry comes in, chemistry allows us to dig deeper and to learn about what goes on beneath the surface of this leaf, it allows us to discover what reactions are occurring and what influences the colour of the leaf.
9.When synthesizing new chemicals with potential uses scientists must be very cautious as it could have many other effects and reactions to everything around us. This was seen in the case of CFCs, at first they seemed very useful and did not react to other chemicals but over time they caused ozone levels in the atmosphere to decrease. So, for any new chemical that is synthesized it is very difficult to predict what will happen and what effect it may have, therefore scientists need to be very cautious.
10. If weight is 120 pounds and mass is 54 kilograms then on the moon my mass would be the same (54 kilograms) and my weight would be 1/6 of that on Earth. This is because mass will not change whereas weight, which is basically a measurement of gravity’s pull will change. Therefore, as the moon’s gravitational force is 1/6 of Earths, my weight would be 20 pounds and my mass would be 54 kilograms
11. The scientific method is an organized process by which scientists do research and are able to verify the work of others. The steps vary from scientist to scientist but in general they are, observation, hypothesis, experiment and conclusion.
12.The independent variable would be the temperature as that is what you are putting in to the experiment. The dependent variable would be the size of the balloon and the constant would be the amount of air in the balloon. A control would have to be constructed and could be done by filling the balloon with air at room temperature and measuring it’s volume. Then it could be heated or cooled and the volume compared to that of the room temperature balloon.
13. Molina and Rowland’s hypothesis is strong in that there is evidence showing ozone levels decreasing while CFCs rise however it does have it’s weakness as well. As they are referring to ozone and CFC levels in the atmosphere it is difficult to say that there is a direct correlation between the two. This is because there are many other elements and chemicals present in the atmosphere which could have led to ozone levels decreasing. Or it could even be a natural process for ozone levels to vary just as temperatures on Earth have, moving from ice ages to heat waves and so forth. So, while there is evidence to suggest that their hypothesis is correct there are also other factors that weaken their hypothesis.
14.It should be a law because the gases will never change; therefore a certain temperature will always have the same effect on the volume of the gases at constant pressure. If gases were to change their properties or how they react to certain variables such as temperature then it would not be a law, but seeing as gases will always be what they are (oxygen will always be oxygen, helium will always be helium… etc.) and will always react in the same way that they do now then Charles’s description would be called Charles’s law.
15. Molina and Rowland’s data in the lab must be supported by measurements take in the stratosphere because the data collected in the lab will have been more controlled than that in the stratosphere. Therefore, the data in the lab could have had a completely different outcome to what the stratosphere data suggests; it could have been that under controlled circumstances CFCs do not impact ozone levels but in the stratosphere the more CFCs there are the less ozone there is. So data must be collected from both sources in order to see if there is a correlation between the two, which could be crucial in either supporting or rejecting their hypothesis. Also to prove a hypothesis they would have needed to collect as much data as they could to ensure an accurate conclusion.
16.It would be considered a hypothesis because if no data is provided then there is no evidence that it is true or even that it has been tested. For it to be a conclusion it would need data to support it so as there is no data it must be a hypothesis.
Questions for Chemistry:
1. How have we advanced in the study of medicine?
2. How are diseases cured?
3. How are we able to start fires from something as small as a match?
4. How are we able to think?
5. Why are certain crops able to withstand climates which they are not usually associated with?
6. Can we stop/cure mental illnesses?
7. Will we ever completely cure allergies?
8. Are “designer babies” actually a possibility?
9. Will airplanes ever be eco-friendly?
10. How are airplanes able to stay airborne?
pH and Temperature Collected Around The School
The first thing that stands out about the graph and data is that there is no correlation between the pH and Temperature of the water. There are however pH levels which vary from 6.48 – 8.42 which is a bit odd as it was all rain water from the same day. This could suggest that there were things in the water which might have affected the pH, such as the mud, moss, leaves...etc. The temperature in general remained close to the same, varying but not much more than one degree C, until; the rain gage and fresh rainwater were tested. The rain gage had a temperature of 27.9 degrees C whereas the fresh rain water was 20.6 degrees C; as all of the other temperatures seemed to stay in the 25-26 degree range this was quite a significant drop in temperature. A possible explanation for this could be that all the other temperatures had been taken from water which had collected either on the ground outside or in a plastic rain gage, also outside. Which would have been exposed to the sun and heat before being tested so they would have had time to become warmer; whereas the fresh rainwater had been collected while it rained and was then kept indoors in a glass beaker. Another explanation could be that the ground may have been quite warm before the rain, so, as the rainwater collected, the heat of the surface or ground warmed the temperature before collection.
Blood Pressure Experiment (edited)
Research Question:
How does blood pressure change in isometric training as compared to isotonic training?
Hypothesis:
If blood pressure rises more when a person is performing exercises involving movement then the blood pressure will be higher in isotonic training as compared to Isometric training.
Materials:
-blood pressure sensor
-pen & paper for any observations
-data logger
-computer
-gym mat
-wall
-2 or more volunteers
Independent Variable: Type of exercise
Dependent Variable: Blood pressure
Control Group: Blood pressure while resting
Experimental group: Blood pressure while/after resting
Controlled Variables: Age of volunteer, amount of time for each exercise, exercise done, resting time between exercises
Procedure:
1. Explain to the volunteers that they will be performing 4 different exercises each for a certain amount of time while their blood pressure is being collected.
2. Connect the data loger and blood pressure sensor to the computer and power supply and make sure everything is working.
3. Have the first volunteer sit while wearing the sensor for 30 seconds then press “collect.” Let the sensor run for 30 seconds and record the average resting blood pressure into the table.
4. Now have the same volunteer stand still and record the average standing blood pressure.
5. The same volunteer will now start the first exercise (sit-ups) for 30 seconds while the average blood pressure is recorded
6. Let the volunteer rest for 30 seconds then repeat the exercise for 45 seconds and record the average blood pressure
7. Repeat steps 5 & 6 for each of the chosen times, letting the volunteer rest for the same amount of time that they have exercised each time (ex. Exercise for 1 minute then rest for 1 minute then move on)
8. Let the same volunteer rest until the blood pressure goes back to the original sitting pressure
9. Repeat steps 3-8 with the same volunteer for push-ups
10. Repeat steps 3-8 with the same volunteer for the wall sit
11. Repeat steps 3-8 with the same volunteer for the plank
12. When the first volunteer has completed the first trial for all the exercises move on to the next volunteer and repeat steps 3-11
13. Once all the volunteers have repeated the first set of trials go back to step 3 and repeat everything for trial 2
14. Go back to step 3 and repeat everything for trial 3
15. Finally, graph the collected data and try to draw an accurate conclusion
For the wall sit the volunteer must have their back upright against the wall and their knees bent at a 90 degree angle and must hold this position for the entire course of the given time. For the plank the volunteer must get into the push-up position with their back straight and hold it for the entire length of time given.
Blood Pressure Experiment
Research Question:
How does blood pressure change in isometric training as compared to isotonic training? VERY GOOD!
Hypothesis:
If blood pressure rises more with isotonic training/exercises then it will be higher than with Isometric training/exercises. This is unclear Jade, what is the prediction?
Materials:
-blood pressure sensor
-pen & paper for any observations
-data log ger
-computer
-gym mat
-wall
-2 or more volunteers
Independent Variable: Type of exercise
Dependent Variable: Blood pressure
Control Group: Blood pressure while resting
Experimental group: Blood pressure while/after resting
Where are your variables to be controlled
Procedure:
1. Connect the data log and blood pressure sensor to the computer and power supply and make sure everything is working.
2. Have the first volunteer wear the sensor and press “collect.” Let the sensor run for 30 seconds and record the average resting blood pressure into the table. what is the volunteer doing to be resting?
3. Place the gym mat close enough to the data log so that the cables reach and the volunteer is able to move without interference. Explain to the volunteer that they will now have a certain amount of time in which they must try their best to complete the given exercise (you should also explain which exercise they are starting with (you will have to move everything near to a wall for the wall sit)). THIS SHOULD OCCUR PRIOR TO START,MIGHT THIS ALSO AFFECT BLOOD PRESSURE?
4. When the volunteer is ready press “collect” and let them begin. Let the data log run for the time set (30 sec., 45 sec., 1 min. or 1min.15) then stop the data log and record the average blood pressure.
START WHAT? YOU NEED TO TELL WHICH EXERCISE.
5. After each exercise let the volunteer rest for the same amount of time that they have been working (ex. If the exercise lasted 45 seconds they will get 45 seconds of rest before the next one).
6. Repeat this process for each length of time, with 3 trials for each exercise and time.
7. Record the blood pressure at the very end aswell. SENSOR WILL RECORD THROUGHOUT .
8. Finally, look over the data collected and graph the results, then try to form a conclusion based on the collected data. You might have to repeat or change the experiment if necessary. NOT NEEDED.
For the wall sit the volunteer must have their back upright against the wall and their knees bent at a 90 degree angle and must hold this position for the entire course of the given time. For the plank the volunteer must get into the push-up position with their back straight and hold it for the entire length of time given. WHEN DOES THIS HAPPEN? YOU NEED TO BE SPECIFIC.
OVERALL A GOOD JOB, YOU NEED TO WORK ON YOUR WORDING FOR YOUR METHOD/PROCEDURE . WELL WORDED QUESTION.
(homework)
The Scientific Method
The scientific method is a process by which a problem is solved or a theory is tested. It can also be said that it is the base of everything that is done in science and many of our day-to-day processes whether we realize it or not, it is an essential part of science and life in general. If you really think about it, one way or another everything man-made around us has been made through some form of the scientific method. - good explanation dont have much to critisize
The scientific method involves several steps which are: making an observation/identifying a problem, forming a hypothesis (usually an “if…” and “then…” statement). Then carrying out experiments and making observations in order to test the hypothesis, collecting and analyzing data. (maybe more steps like research and what the hypthesis is) Finally, a conclusion is drawn and the initial hypothesis is either supported or rejected. If supported then the results are communicated or told to others. However, if the hypothesis is rejected then a new hypothesis can be formed and tested or the experimental stage can be re-done to make sure that there were no errors. Even though this process is known to all scientists and many others it does not mean that they will all list the same steps. For example, different sources on the internet will have a different number of steps or call them different names or even have them ordered differently. They might have research before the hypothesis or might group together different steps and not every source includes the communication of results at the end. Now this doesn’t mean that the scientific method has changed, it is still the same universal method, however, as everyone is different they will see it differently and many might find some steps unnecessary to list.
The scientific method, as you can imagine, is an essential part of a scientist’s daily work. Without it they would have nothing to test or discover. Scientists use the method in a variety of ways. For example, if a scientist suddenly notices that the plants on the right side of the room look healthier than those on the left and that it is lighter on the right side, then the scientific method has already been put into play. From here the scientist could say that if the plants on the right are receiving more sunlight then they will look healthier than those on the left. Then relevant research would be done and experiments carried out and so forth. This happens every day for scientists, who test and experiment with everything from the effect of coke on plant growth to cures for diseases like dengue or cancer, and discover things that make our lives better and easier which would not be possible without the scientific method.
Now it is not only scientists that use the scientific method, we use it as well, most of the time without realizing it. In math we use it to solve problems; in art we use it to create paintings and drawings. We even use it while driving to school. We think, “If I take this road then there will be less traffic” and we proceed to test this theory and then based on what time we get there we judge whether it was a good choice or not. In technology the design cycle is used which, if you think about it, is just like the scientific method. You start by investigating a problem then planning, creating a solution and finally evaluating your work. So, the scientific method is all around us whether we know it or not.
( good, which can be associated with anyone) - your everyday life situation, but you could expand on the situation
theres not much to expand on, this is well done
Sources:
http://scifiles.larc.nasa.gov/text/kids/Research_Rack/tools/scientific_method.html
http://teacher.pas.rochester.edu/phy_labs/AppendixE/AppendixE.html
http://sciencebuddies.com/science-fair-projects/project_scientific_method.shtml
http://school.discoveryeducation.com/sciencefaircentral/Getting-Started/Investigation.html
pH Lab
Materials
- Data log some of this info was cut off the page but seems to be pretty good
- Computer
- pH sensor
- Various liquids and household cleaners
- Three 100ml beakers
- A 400ml for the cooler water
- Pen and paper to make observations
Method
Before starting the experiment make sure that a table has been made including each liquid that will be tested with two additional columns one for the predicted pH and one for the actual pH. Also make sure to write your pH predictions before testing any of the liquids.
1. Connect the data log and pH sensor to a laptop/computer
2. Fill the 400ml beaker with roughly 200ml of cooler water (filtered water taken from the water cooler) then place the sensor in it. Click on “collect” and let the data log run for 30 seconds.
3. Stop the data log and find the average pH and either write it down or type it into a table.
4. Fill the three 100ml beakers each with 40ml a different solution and place the pH sensor in one of them, click “collect” and let it run for 30 seconds then record the average
5. Repeat this with each of the 3 beakers, making sure to rinse the pH sensor in the cooler water between each reading
6. After testing those liquids, empty, rinse and dry the beakers and choose another 3 different liquids and replace the cooler water, then repeat the process until all the liquids have been tested.
7. After all the results have been tested look through the table and compare the predicted pH to the actual pH, then make a graph and write your conclusion.
*It is advised to test waters first (salt water, tap water, cooler water) and liquids such as lime juice, Disiclin and Cola last as they may affect other readings. - great method, lots of explanattion
Data Table
Results (graphed)
Conclusion/Evaluation
I think overall the predicted pH’s where quite close to the actual pH apart from the predictions for the two alcohols and the disiclin. Most of the groups thought that disiclin would be more of a base when in fact it turned out to be an acid; and the alcohols were thought o be either bases or acids but turned out to be quite close to 7 (the neutral). Another observation which is quite interesting to note is the difference in pH readings for the 50% alcohol. In all the other data the differences between the pH’s is usually off by one or two but in this case the pH readings were 7.89, 8.233 and 4.65 which is a bit strange because it was the same substance being tested but it gave two similar readings and one that was completely different. I think in the future if this lab were to be repeated a hypothesis should be created and the pH of the substances could be tested under various conditions to see if something like temperature could affect it or if the amount of time the sensor is in the beaker changes the pH.
Great job jade i have nothing to critisize haha really but maybe a bit of clarification on the odd sentance but other then that its good.